8m x 30m Hot Dip Galvanized Steel Tunnel Greenhouse 200 Micron UV Resistant PE Film Cover

An 8 m x 30 m single span tunnel is the size most growers settle on after comparing their third or fourth quote. It is wide enough for four 1.2 m beds with a 0.9 m centre path, low enough in profile to shed heavy rain quickly, and short enough that a two person crew can re-skin the whole house in a day. This unit is built from 60 x 2.0 mm round steel tube, hot dip galvanized after welding at 275 g/m2 zinc coverage, then covered with 200 micron five layer co extruded PE film. Roof height is 4.0 m and shoulder height 1.8 m, with arches at 1.0 m centres. It ships as a bolted kit: no welding on site, no concrete pour beyond the anchor points marked on the foundation drawing we send with the container.

• Hot dip galvanized after welding: 275 g/m2 zinc on the finished arch, measured with a coating gauge on every fifth arch before packing. Salt spray class C4, roughly 12 to 15 years of service in coastal air.
• Five layer 200 micron film: Co extruded with a 3 percent UV blocker in the outer ply, 90 percent light transmission, 0.5 percent haze and a 36 month warranty against UV cracking.
• 1.0 m arch spacing with three purlins: Load path designed for 0.45 kN/m2 wind and 0.30 kN/m2 snow. Closer spacing than the 1.5 m pattern common on lighter kits, so film flap and purlin sag stay small.
• Bolted joints throughout: M10 hot dip galvanized bolts with nylon washers, cross braced at the gable ends. Any farm hand with two 17 mm spanners can assemble it.
• Manual roll up ventilation on both sides: Full length 1.5 m roll up curtains with 40 mesh insect net behind, aluminium lock channel and a 5:1 gear winch at each end.
• Documentation set: Foundation drawing, bolt schedule, film tension sequence and a 14 minute installation video in English, Spanish and French.

Two figures separate a tunnel that lasts twelve years from one that looks tired after three: zinc weight on the steel, and UV stabiliser in the film. Ask for both in writing. A pre galvanized tube with a sprayed touch up coat usually measures 60 to 80 g/m2 and starts rusting at the drill holes and crop ends within two seasons. Our arches are dipped after all holes are punched, so the zinc flows through every bolt hole and the cut ends are sealed by the process itself. On the film side, a 200 micron nominal roll can arrive at 150 micron at the thin points; we measure six points across the web and record the minimum on the packing list. If a supplier cannot show you the measurement, the thickness claim is marketing rather than specification.

The house is sized following EN 13031-1 practice for a 0.45 kN/m2 design wind speed, which covers open field sites in most of Europe, Central Asia and East Africa. Three continuous purlins tie the arches together, and the end frames carry diagonal bracing in both directions, so the structure resists racking rather than relying on the film for stiffness. Snow capacity at 0.30 kN/m2 suits light to moderate snow zones; for heavier snow the same frame is available at 0.8 m arch spacing or with a gothic arch profile. Roof pitch and gutter detail move rain to the sides instead of pooling above the shoulder line, and the 140 mm/h rain figure is the drainage rate of the curtain trench when the roll up is closed.

Ground preparation matters more than most buyers expect. Level the pad to plus or minus 20 mm over the full 30 m, compact it, and set the anchor points on the supplied drawing at 1.0 m centres. A crew of three normally stands the arches in two days and fits the film in one more; the film should be fitted in the morning while it is slack, because PE tightens as the sun hits it. Two scaffold towers, a 3 m spirit level and a cordless driver are enough tooling. We include 5 percent spare bolts, four extra film clips and one spare roll up winch with every set.

Tomato, cucumber, pepper and leafy green growers use the 8 m width because it gives four working beds without a central post. Strawberry and herb farms run it as a low cost rain shelter with the sides fully open. The same frame is used in Kenya and Ethiopia for rose propagation, in Uzbekistan and Kazakhstan for early tomato, in Spain and Portugal for berry extension, and in Indonesia and the Philippines for tropical leafy greens where the roll up sides are opened by 7 am. Export packing is designed for a 40HQ: one complete 8 x 30 m set plus 10 percent spares occupies about 26 cubic metres.

Every set passes five checks before it is allowed into the container: incoming coil certificate, weld penetration on a sample arch, zinc thickness on a finished arch, a pre assembly trial of one bay, and a film tensile and UV test report from the film mill. Bundles are wrapped in woven fabric, film rolls travel in a carton with a desiccant bag, and all steel parts are banded onto fumigation free pallets. The frame carries a 10 year structural warranty and the film 3 years against UV degradation, with spare arches, clips and curtains held in stock for at least 10 years after your order. Loading photos and a container packing list are sent before the truck leaves the yard.